As Bill.Satellite wrote seasonal rental is always and option. And does have the advantages he mentions. We also considered that. But we found some disadvantages to that too. So I guess the advice is...It all depends on what you want.
Here is why we steered away from the seasonal idea. First of all the campgrounds we researched were privately owned for profit campgrounds. And they varied quite a lot in their services, and style. But one thing we found was that for the most part the owners, were quite cost conscious. And would avoid spending money for landscaping, and maintenance. They were more interested in taking money out than putting money in. Basically they did the minimum they needed to. We didn't find any seasonal campgrounds that were nice enough that we really wanted to spend six months in.
Location...The private campgrounds were typically very close to major roadways. Don't know why, really. But I suspect it to be because the cost of land was much more reasonable. The ownership campgrounds are generally developed with sales opportunities as the primary strategy. So they are in more desirable locations. Away from heavy travel routes, trains, airports, etc.
And in the interest in building their revenues, private rental camps tend to squeeze campers in real tight. So the sites can be quite concentrated.
Because they are private campgrounds, you may have neighbors that are short term campers that are on vacation. Generally, not a problem. But sometimes you get what you get. And maybe not the best to your liking. This can happen in an owned site too. But the chances are much less.
The owned campsite has the advantage of increasing in value if you ever need to liquidate. With a private seasonal campground, you don't have the problem of selling it. But once you spend your money, it is gone.
There are more considerations too. You have to be careful if selecting an ownership site. I will add those in another post.